Soulkeep
by Master Nenva
Summary: He's the Judge. It's his job to keep the monsters safe and the humans at bay. Nobody ever told him it would be this hard.
1. The Failed Reaping

Far underground, in the heart of Mount Ebott, the world of monsters was silent. The only sign of life was a lone skeleton standing at the guest room window. He wore a blue hoodie and leaned against the window with his hands jammed in his pockets. If he squinted, he could just barely see the glittering snow of Snowdin. One of his eye sockets lit up as his pupil glowed blue. He squinted, trying to pick his brother's Soul out of the hundreds he could see, but the avalanche of numbers became too great and he was forced to stop his search.

"Wish you were here, bro," he said as his eyes went back to normal.

Someone knocked on the door. "Sans! I know you're awake! Answer the door before I break it down!"

Sans turned toward the door. His gaze flickered to the bedside cabinet where a black cloak and leather book rested side by side. He crossed the room and put the black cloak on, then stuffed the leather book under his sweater. He didn't bother turning toward the door. "Come on in."

The door opened and a soldier stepped into the room. She pulled off her helmet, revealing blue scales and an eye patch. She grinned a fanged smile. Sans tipped an imaginary hat at her.

"Came to say goodbye, Undyne?" he asked.

"Are you kidding me? You can't leave! We need you here!"

Sans shrugged. "I don't know why I came here in the first place. Asgore won't listen to me. Besides, I've left Papyrus home alone long enough."

"But you're leaving now? In the middle of the night?"

Sans grinned. "Yes. But I can trust you to keep an _eye_ on things, can't I?"

"This isn't the time for your jokes!" Undyne folded her arms and grimaced. Sans smiled.

"It's always the time for jokes."

"What's eating you, Sans?"

Sans hesitated. The leather book felt warm against his chest. Undyne wouldn't betray him. Not Undyne, who was alone patrolling the castle even when King Asgore insisted it wasn't necessary. Not Undyne, the only monster in the entire kingdom who believed a Soul reading was necessary.

But if he told her, and she decided to do something rash . . .

"Just a feeling," Sans said. "It's not a _grave_ situation. I still have a _bone_ to pick with the kid, but there's no point to _digging_ for answers."

"Sans!"

"But hey, if it makes you feel better you can walk me to the door."

She growled, but stepped out into the corridor anyway. Sans followed close behind. They walked side by side down the dark, empty halls.

"Is Papyrus still-?" Undyne asked, but Sans held up a hand to stop her. He narrowed his eyes. They had reached the throne room, but they weren't alone. He could see somebody's numbers. Somebody with a high LV. He pressed a hand against his shirt to check that the tome was still there before proceeding into the throne room.

A lone figure slumped against the Queen's throne, clutching at it with one trembling paw. Dust drifted off of his white fur like starlight. He was wearing his pajamas, eyes closed as his chest fought to rise and fall.

Prince Asriel.

Sans ran to the Prince's side as Undyne's spear materialized in her hands.

"Asriel," Sans whispered. He gently took hold of the frail Prince's shoulders. "Asriel, we're here. What happened?"

"Isn't it obvious?" Undyne asked. "Someone, or some_thing_, attacked him!"

Sans swallowed. The monster with the high LV. He pulled the leather book out from under his cloak and stood, turning to find the villain. The prince had been hurt recently. The attacker couldn't have gone far. They would have wanted to make sure the job was done.

Undyne growled as they spotted the shadowy figure in the doorway. _She_ was here. Dust trickled from her fingers and smeared her striped green shirt, but still Sans hesitated. That dust could have meant anything. Maybe she had found the prince, tried to help him, and then gone looking for help. The king and queen trusted her. That had to count for something, didn't it?

Sans swallowed. He couldn't afford to be uncertain. He had to know. He had to know _now_, even if the king and queen hadn't agreed to a Soul reading.

Her chest glowed. Slowly, painfully slowly, a deep gray heart stained with rivers of red molten hate emerged to hover between them. Undyne took a step back, while Sans took a step forward. He had never seen a human Soul before. They weren't that different from the Souls of monsters. They were even the same color, aside from the red streaks.

"Well?" Undyne asked as she glanced back at Sans.

Sans hesitated. As he stared at the Soul he knew how much EXP the kid had. But he also knew it was lower than it should be if she had attacked the prince. How was it possible? Sans knew she was involved with the dying Prince. But the reading declared that she wasn't evil. The reading couldn't be wrong, could it?

"Sans . . . please . . ."

Sans looked down at the Prince. Tears dripped from his snout. His fingers were starting to dissolve into dust. Sans turned away.

"Sans, is she good or not?" Undyne asked.

"Why even bother asking?" the little girl said. "Isn't it obvious? Sans is _weak._ He couldn't figure this out until now, and it's too late! Nobody can stop me!"

"_I_ can still stop you," Sans growled.

"No," Undyne said. "Let me handle this, Sans."

Sans's eye began to glow as he grinned. "No, it's my turn, Undyne. Kid, I'm the Judge. Stopping you is my job. You, human, will answer for the murder of Prince Asriel."

"Are you stupid?" the human asked. "You can't take me. Especially not now."

She reached into her pocket and drew a knife, but Sans was quicker. He summoned a skull in the air beside him and kept smiling. The skull roared to life and blasted her with a beam of white light. She howled as her Soul was ripped from her body. Sans snatched the Soul from the air, now almost entirely red, and pressed it into the open pages of his book. He slammed it shut. Silence reigned as her body crumpled to the ground.

"Sans," Undyne said softly, "I've never seen . . . Is she in there?"

"Where she belongs," Sans replied as he patted the leather cover. It felt warm under his skeletal fingers. He sighed. "Where she can't hurt anybody."

Undyne glanced over Sans's shoulder. Her eye widened. "The Prince!"

Sans couldn't reply. Horror seeped into the marrow of his bones. His eyes were caught on the human. She was still there, trembling on the ground as she pushed herself to her hands and knees. She shouldn't be alive. She _couldn't_ be. Her Soul . . .

"You can't stop me," she whispered. Her voice was sandpaper, rubbing against his will, scraping away his hope until none was left. "You're a fool, Sans. I . . . can't . . . die. I'll destroy you. I'll destroy you _all_!"

Her body rippled and vanished, leaving only drifting dust particles and the echoes of her deathly laughter. Sans stood still as the shock of it all sunk it. He had failed. He had taken her Soul, but She was still alive. And She had escaped.

"We're in trouble," Undyne said.


	2. Snow and Monsters

_\- - - Many Years Later - - -_

Sans always did his most serious thinking when Papyrus wasn't home. That had been happening more often lately as Papyrus stepped into his duties as Snowdin's leader, which was both a blessing and a curse. It wasn't that Sans didn't appreciate the time to think; he was simply starting to wonder if all this thinking was doing him any good. It wasn't as if he could actually do anything about the problems on his plate.

Sans paced his bedroom floor as he tapped his skull. His eyes flickered to his cabinet. He hesitated, then shook his head.

"No. I'm not pulling it out."

He walked to the cabinet and opened the top drawer. It was empty except for a worn leather book. The Soul Tome. He slammed the drawer shut again.

"I need a walk," Sans said. It didn't take long to leave the room and cross the empty house. Moments later the skeleton was standing outside in the snow, whistling to himself as he jammed his hands in his pockets.

Snowdin was alive with activity. The local residents were placing gifts underneath the tree in the center of town while their kids built snow-monsters. Everywhere Sans looked, he could see happy monsters. He smiled. "Maybe Papyrus is right. I really do need to get out more."

"Hey! _Hey! Sans!"_

Sans glanced over. He could just barely spot Monster Kid jumping up and down beside a lump of snow. Monster Kid was grinning ear to ear and a wooly cap had been jammed on his yellow scaled head. Sans chuckled as he walked over.

"What's up, kiddo?"

Monster Kid nudged the pile of snow with his foot. "We're having a snow-monster building contest. Could you help me make one of Undyne?"

"But isn't that cheating if I help you?"

"Nuh-uh! Besides, you're Sans! You probably know Undyne best!"

_More than you know, kid,_ Sans thought. He started rolling the snow into a big cylinder. "Sure, I'll help. I haven't done this is ages; not since Papyrus has been so busy."

Monster Kid's eyes sparkled. "You used to build snow-monsters, too? Do you think Undyne did?"

"I think Undyne fights snow-monsters." He picked up a branch and stuck it into the ground beside the cylinder. "There, all done."

Monster Kid tilted their head. "That's it?"

Sans shrugged. "Sure. What else does it need?"

"But . . . it's just a tall pile of snow! With a big stick next to it!"

"That's her spear."

Monster Kid glanced over Sans's shoulder. "Never mind, Sans. There's Papyrus. Maybe he'll help me build Undyne!"

Sans followed Monster Kid's gaze. It _was_ Papyrus. He was standing with his back to them, holding the door open and talking animatedly to someone. Sans smiled.

"I'm sure he would be happy to help you, kiddo," he said. "I'll go ask him."

Snow crunched under Sans's feet as he rounded the house to stand beside his brother. "Hey, Paps."

Papyrus spun around. "Sans! Just the skeleton I was looking for!"

"Really?"

"Yes! Sans, I just found the best-"

Sans leaned closer. "Because it shouldn't be hard to find a _lazybones _like me."

Papyrus stomped. "Sans! This is serious! No puns!"

Sans shrugged and winked. "Can't help it. It's in my _bones_."

"You already used bones in a pun!"

Sans smiled. "Must be a good one, then. You know, it's good to see you out and about, Paps. I'm glad you finally got over the whole castle guard thing."

"Over it?"

"You're right, poor choice of words." Sans gestured vaguely. "I'm glad you're taking being a leader seriously. Everyone needs us right now, and we can't help them if we spend all our time with that border post . . . and, you, know . . . looking for humans."

Papyrus fidgeted with his gloves. "Sans, what if I found one?"

"Found what?"

"A human."

Sans's heart stuttered. He fought to keep a smile on his face. _If you really found a human, you wouldn't be alive right now. You can never, never trust a human._ "If you found one, I'd take care of it."

"Right! And I could help, too! We'd make it spaghetti, and it could sleep on our couch!"

Sans gave him a long look. "That's not what I meant."

The two brothers stared at each other. Papyrus reached behind him and slammed the front door shut. "Right. So we could talk about it."

" . . . No."

"But Sans-"

Sans narrowed his eyes. He pulled his hands out of his pockets. "Papyrus, what's going on? What are you hiding?"

"Hiding?" Papyrus held up his hands. "I'm not hiding anything, brother! I just want to discuss is all."

Sans's eye began to glow bright blue. He pushed past Papyrus and threw open the front door. He froze, heart missing several beats in his chest when he saw who was standing just inside beyond the door.

A human.


End file.
